Many cleaning compounds have been formulated over the years that have incorporated a solid particulate material as an abrasive to aid in the cleaning process whereas the surfactant and solvent components of cleaners chemically interact with the organic deposits that comprise the undesirable stains, film or "dirty" appearance thereon. Abrasives, through forceful agitation, scrub the surface and physically remove the deposits that are difficult to clean chemically. Once physically broken up, the deposits are more susceptible to chemical breakdown by the surfactants, solvents and detergents.
Abrasives have been used for years in household cleaners, hand soaps, denture cleaners and the like. Pharmaceutically acceptable and food grade compounds have also been used in oral compositions to assist in the breakdown and removal of plaque, tartar, and food stains from teeth. U.S. Pat. No. 4,081,526 to Asakawa et. al. discloses and claims a dentifrice composition with increased polishing power for the removal of plaque and tartar using an abrasive comprised of a combination of an alkali metal phosphate and 0.5 wt % to 13.0 wt % of either monomorillonite or hectorite. The monomorillonite fraction consists of silicon dioxide, magnesium oxide, sodium oxide, iron oxide, and disodium oxide while the hectorite fraction is comprised of a mixture of the same components in different percentages. It is alleged that the combination of the abrasive components produces a synergistic effect, not only in the removal of the plaque and tartar from the surface of the tooth but in the prevention of subsequent plaque deposition.
U.S. Pat. No. 4,871,396 to Tsujita et. al. discloses toothpaste formulations wherein water insoluble binders such as colloidal silica, calcium silicate, montmorrillonite, and magnesium hydroxide, among others, are used to prepare microparticulate granules for use as an abrasive on the surface of the tooth. The granules themselves are comprised of dibasic calcium phosphate, sodium metaphosphate, magnesium carbonate, and mixtures thereof. The granules allegedly serve as excellent polishing abrasives on the tooth surface which results in a pleasant mouth feel.
U.S. Pat. No. 5,149,521 to Hirose et. al. discloses a dentifrice composition comprising a breakable granule consisting of a powder material selected from the group consisting of calcium phosphate, sodium metaphosphate, calcium carbonate, aluminosilicate and the like. The powder material is formed into the granule using a binding agent, resin, fat, polymers, or oils. The breakable granule does so when scrubbed against the tooth during brushing and allegedly imparts a smooth, polished organoleptic feeling in the mouth.
U.S. Pat. No. 5,206,010 to Inoue et. al. also discloses toothpaste formulations comprising abrasive microparticulate granules that consist of a water insoluble powder and a water insoluble organic binder. The water insoluble powder is comprised of sodium metaphosphate, calcium pyrophosphate, magnesium silicate and the like. The binders consist of fat and oils, polymers of methacrylic acid esters, vinyl acetate, PVP, thermoplastic resins and the like. Pharmaceutical agents may also be incorporated for a medicinal therapeutic effect. Again, the granules are processed so as to breakdown during brushing and impart a slippery, smooth mouthfeel.
Published PCT Application No. PCT/EP95/03698 to Vernon et. al. discloses toothpaste compositions containing abrasive agglomerates consisting of silicas, aluminas, calcium carbonate, calcium phosphate, hydroxyapatites and dicalcium phosphate, among others. The agglomerates break down with brushing and are designed to impart a sensorially perceived cleaning benefit without the usually affiliated gritty mouthfeel. The agglomerates are free of binding agents but are comprised of at least two of the enumerated materials, each of which are chemically or physically different from the other.
Published PCT Application No. PCT/EP95/03560 to Stanier et. al. also discloses toothpaste compositions comprising granular abrasives to impart a polished, clean mouthfeel to the teeth. The granules are also comprised of at least two different materials, a high structured water insoluble particulate, (i.e., one with a high oil absorption capacity) such as aluminas and expanded perlites with a low to medium structured water insoluble particulate material (low oil absorption capacity) such as amorphous silicas, calcium carbonate, dicalcium phosphate and the like. The particles also break down in the mouth with the application of shear and aid in the removal of tartar and plaque.
None of the prior art compositions afford a granular microparticulate abrasive comprised of only one material without the need for additional binders and/or agglomerating agents. Nor do any of the prior art materials provide a granule whose particle size is readily controlled and variable depending on the application of use.